Power supplies are a crucial component of most electronic equipment. A power supply commonly converts electricity from a supplied form to a form used by the components of an electronic device. For example, a power supply may convert an AC input to precisely regulated DC voltages. Efficient operation of the power supply is desired to avoid excess energy consumption and because the excess energy is dissipated as heat. Even when a power supply is efficient, it may be a substantial and concentrated source of heat in an electronic device.
A limitation of electronic equipment is inadequate cooling of components of the equipment. Inadequate cooling can impair reliability and impair performance. For example, device reliability may decrease exponentially as the temperature of the device increases. Additionally, a device's performance may degrade as the temperature of the device increases or the performance of the device may need to be lower to avoid excessive temperatures.
Many electronic devices are cooled by air forced over the components by fans. For some electronic devices this is not practical. For example, electronic devices that are to be located outdoors in a harsh environment may be in sealed enclosures so that the components of the devices are protected from the harsh environment. Electronic devices deployed outdoors may be subjected to temperature extremes, for example, −40° C. to 55° C.
Switching power supply techniques are commonly used in many electronic devices. Switching power supplies may be more efficient than power supplies using other techniques. The efficiency may be increased by increasing the switching frequency. However, switching at higher frequencies may cause electromagnetic interference problems when transients associated with the switching couple or radiate from the power supply.